During the manufacture of display panels such as a liquid crystal display (LCD) display panel and an active-matrix organic light emitting diode (AMOLED) display panel, a plurality of testing processes are required, and among which an important testing process is a cell test (ET) on the display substrate after the cutting process, to determine whether it is defective. The ET test is performed before the driving chip and the flexible circuit board are attached to the display substrate, wherein the flexible circuit board is used for inputting display signals.
The ET test is generally performed by inputting a test signal to the display substrate through a light-on device such that the pixels in the display substrate may present colors, and then observing whether each pixel is defective by the defect detecting device. This process is referred to as a light-on test.
In order to facilitate the test, a testing pad is generally provided on the display substrate (usually the array substrate), and a testing pin of the light-on device is in contact with a test spot on the testing pad, wherein the test spot is connected to a signal line. Accordingly, a testing signal may be input to the signal line through the testing pin and the testing spot to detect whether the display substrate is defective.
A driving chip is provided in a peripheral area of the display substrate. The signal line is provided between the driving chip and the pixel units in the display substrate to establish connection therebetween. The testing pads are provided at both sides of the driving chip and are connected to the signal line.
Pin miss is a frequent device abnormal during the light-on test. Since it is impossible to tell a product defect of the display substrate itself (display abnormal) from the pin miss abnormal only according to the result of the light-on test, problems such as misjudging a good product as a defective product may occur during the manufacturing.
In the related art, in order to determine a pin miss, if a display abnormal has occurred, the inspector takes the display substrate off the testing desk and repositions the display substrate several times to confirm whether there is a pin miss. Such a scheme is time consuming, accuracy unreliable, and susceptible to the inspector's skill.
It should be noted that, information disclosed in the above background portion is provided only for better understanding of the background of the present disclosure, and thus it may contain information that does not form the prior art known by those ordinary skilled in the art.